The American Beauty (La Belle Americaine) (1961)

Marcel, a simple-minded factory worker, is tricked into buying a high-priced American convertible by a widow determined not to let it fall into the hands of her late husband's secretary/secret lover. Once in possession of the car, Marcel only encounters one bad luck episode after another with the excessive gasoline consumption, his wife trying to sell it to make ends meet, getting into traffic jams, accidentally riding into a car wash with the top down, and more.